Measurement of wind field characteristics at a long-span suspension bridge  

基于现场实测的某大跨度悬索桥桥址区风场特性(英文)

作　　者：胡俊[1] 郭健[1,2] 欧进萍[1] 

机构地区：[1]大连理工大学土木工程学院,大连116024 [2]舟山市六横跨海大桥建设指挥部,舟山316000

出　　处：《Journal of Southeast University(English Edition)》2011年第3期328-334,共7页东南大学学报（英文版）

基　　金：The National Natural Science Foundation of China (No.90815022, 50808160)

摘　　要：In order to provide a reliable basis for wind resistant evaluation of a long-span suspension bridge, a structural health monitoring system is installed on a bridge in the East China Sea and the simultaneous wind data at the bridge deck and at the top of the bridge tower are recorded. The average wind speeds and directions, variations of wind speeds with height, turbulent characteristics, spatial correlation and characteristics of wind flow around the bridge deck are analyzed by using statistical methods and spectral analysis. It is found that the average wind speeds along the bridge girder are almost identical; however, the mean wind directions vary greatly at different locations. The dimensionless exponent decreases as the average wind speed increases. The measured turbulence intensities are greater than the recommended values, and the turbulence power spectrum can well fit the standard spectrum. However, the measured spectral values are considerably smaller in low frequency ranges. The mean wind speed of the wake flow decreases and the turbulence intensity increases significantly, and the spectral characteristics of the wake flow change obviously while the feature frequency of vortex shedding has not yet been observed.为了对大桥抗风评估提供可靠依据,结合东海某大跨度悬索桥的健康监测系统,同步实测了桥面及桥塔处的风速,采用统计及频谱分析方法对桥面平均风速和风向、风速随高度变化、风速的脉动特性、相关性以及桥面风场的绕流特性等进行了分析.结果表明:加劲梁纵向不同位置处平均风速大小接近,但平均风向差别较大;无量纲幂指数随风速增大呈明显减小的趋势;实测的湍流强度比规范偏大,水平及竖向风谱与规范吻合较好,但实测谱值在低频段偏低;风场流过桥梁断面后平均风速减少而湍流强度显著增大,尾流的频谱特性发生明显改变同时尚未观测到规则的漩涡脱落特征频率.

关 键 词：suspension bridge wind field structural health monitoring system field measurement 

分 类 号：U448[建筑科学—桥梁与隧道工程] V321[交通运输工程—道路与铁道工程]